(a) Technical Field
The present invention relates to a mounting structure for a compressed gas storage tank of a vehicle. More particularly, the present invention relates to a mounting structure for a compressed gas storage tank of a vehicle in which at least two high pressure storage tanks are modularized and mounted in a vehicle.
(b) Background Art
At present, as the problem of air pollution caused by vehicles becomes more serious day by day, extensive research aimed at developing a low emission vehicle has continued to progress. As an alternative to gasoline or diesel fuel vehicles, compressed natural gas or fuel cell vehicles have been developed and used.
The compressed natural gas (CNG) is produced by compressing a gas such as natural gas, coal gas, petroleum gas, casinghead gas, coal mine gas, etc. at 200 atmospheric pressure or higher. The CNG does not generate smoke or dust compared with a diesel vehicle, and noise generated by CNG vehicles does not exceed 50% of that generated by diesel vehicles.
Nitrogen oxide, which contributes to ozone formation, produced by CNG vehicles is about 37% of that produced by diesel vehicles, and carbon monoxide and hydrocarbon are as low as 41% and 16%.
The basic structure of CNG vehicles is the same as diesel vehicles, except for the fuel system. That is, CNG compressed at a high pressure is stored in a gas tank, the pressure of the compressed gas supplied from the gas tank through a fuel pipe is reduced by a pressure reducing valve to an operating pressure, and the gas at a reduced pressure is mixed with air and supplied to the engine.
Accordingly, CNG is contained in a fuel tank made of a relatively thick metal material due to the risk of explosion.
However, the fuel tank made of a metal material causes a problem in that it reduces the fuel efficiency of the vehicle due to its heavy weight.
In order to solve such a problem, Korean Utility Model Publication No. 1996-0005988 discloses a fuel tank for a compressed natural gas vehicle with improved flame resistance and impact resistance.
The fuel tank storing CNG and hydrogen gas at a high pressure comprises a cylinder having a hollow interior and a hemispherical dome integrally formed on both ends of the cylinder.
Since the fuel tank stores compressed gas at a low density, the volume of the fuel tank storing the compressed gas is increased and thus one to four fuel tanks are used.
Meanwhile, methods of mounting a compressed gas storage tank on a vehicle, which have been proposed up to now, can be broadly classified into the following two categories:
1) a method of modularizing a high pressure storage system by surrounding a body portion of a storage tank with at least two brackets in the shape of a belt to form a frame and mounting the frame on a vehicle body; and
2) a method of fixing both neck portions of the storage tank using brackets, and directly mounting the same on the vehicle body, or mounting the same on a frame and then fixing the frame on the vehicle body.
However, these methods of mounting the compressed gas storage tank in a vehicle body have some drawbacks in that the weight and manufacturing cost of a fuel storage system are increased since the structure of the bracket in the shape of a belt and the frame is complicated.
Another method has been proposed in which a plurality of tanks are modularized in an impact absorbing cell and the module is mounted in the vehicle body. Still another method has been proposed in which a high pressure storage system is integrated with a rear suspension and the integrated structure is fixed on the vehicle body.
Yet, these methods still have some drawbacks in that an additional configuration must be provided to protect high pressure parts and pipes from an external collision or impact.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.